Cobra Tag

The Cobra Tag ($80) provides a high-tech way to avoid ever losing your keys again. This sensor attaches to your keys (or bag) and enables you to locate it when you use the associated app on your Android or BlackBerry phone. Cooler still, it's a two-way finder: Tap the button on the Cobra Tag, and your smartphone will ring.

Magellan Weather Station Keychain

Magellan's Weather Station Keychain ($22.50) is the perfect gadget for outdoorsy types. Attached to a heavy-duty carabiner, the Weather Station Keychain supposedly can forecast the temperature and humidity anywhere in the world, and also features an alarm clock, calendar, compass, and built-in LED light.

FlipSync Keychain Charge and Sync Cable

Ever find yourself with a dead device and a USB port, but no cable? If so, you may want to check out the Scosche FlipSync II Charge and Sync Cable ($18). The FlipSync, which comes in two versions--one for Micro- and Mini-USB devices, and one for iPhones and iPods--is a tiny USB cable that folds into itself and fits conveniently on your keychain.

Keyport Slide

This isn't so much a keychain gadget as a replacement for your keychain. The Keyport Slide (starting at $39) is a custom keychain that can accommodate up to six different tools, including standard key blades, chipped auto key blades, USB flash drives (4GB, 8GB, and 16GB), a barcode insert for rewards cards or gym membership cards, and an LED light.

Lil' Piggy Power Bank

The Lil' Piggy Power Bank ($36) is a a solar-powered rechargeable 800mA lithium battery that can charge your iPod or iPhone using stored solar power. You can charge the Lil' Piggy Power Bank with solar energy (14 to 18 hours for a full charge) or by USB transfer (2 to 3 hours). A Mini-USB port connects the battery to your iPhone, iPod, or other mobile device.

Audiovox Ecco Personal Pocket GPS Locator

The Audiovox Ecco Personal Pocket GPS Locator ($32.50) is perfect for people who get lost a lot. This GPS locator can store and recall up to three locations, and can guide you back to any of them, as long as you're within a 9999-mile radius (a limitation that shouldn't pose a problem unless you're really lost). And since it fits on your keychain, you'll always be able to figure out where you are.

LaCie ItsaKey USB Flash Drive

Flash drives are the quintessential keychain tech. The LaCie ItsaKey USB Flash Drive (starting at $15) is small and sturdy, and it blends in with the rest of your keys. This flash drive comes in 4GB, 8GB and 16GB sizes and is compatible with both PCs and Macs. If you're not keen on the ItsaKey design, check out LaCie's CooKey, IamaKey, and LabelKey flash drives.

SEGA Arcade Nano Plug-N-Play Keychain

If you're a gamer who loves SEGA Genesis, check out the portable, plug-n-play SEGA Arcade Nano ($19.50). This keychain controller comes with 10 games built-in, along with cables to plug into your TV for awesome SEGA action. This particular version has a Sonic orientation--it features Sonic the Hedgehog, Sonic 2, Sonic Spinball, Sonic Blast, and Alex Kidd, plus five bonus games. If Sonic's not your thing, you can opt instead for a Virtua Fighter 2 version or a Columns version.

Micro Spy Remote

The Micro Spy Remote ($15), as its name suggests, is designed for stealthily changing the TV channel when nobody's looking. But it's also perfect for people who constantly lose the remote. This tiny universal remote includes volume control buttons, channel buttons, a mute button, and a power button, as well as an AV/TV button. It works with numerous TVs, including models from Aiwa, JVC, Mitsubishi, Panasonic, Philips, Samsung, Sanyo, Sharp, Sony, and Toshiba.

Vanguard MCC 42 Keychain Memory Card Case

This keychain isn't as techy as the others, but it's great for photographers, travelers, or people who routinely carry multiple SD Cards. The Vanguard MCC 42 Keychain Memory Card Case ($9) can accommodate six SD Cards, so you'll never have to worry about losing your photos or data again.

HiJack Headphone Splitter Keychain

The HiJack Headphone Splitter Keychain ($10) is ideal if you often wish you could share your music with a friend--in stereo. This keychain lets you split a single headphone jack into two headphone jacks, and it fits all standard-size headphones. When you're not using it, the splitter plugs into a key ring for convenient portability.

Insignia Digital Photo Keychain

The Insignia Digital Photo Keychain ($12) displays photos on with your keychain. This tiny digital photo frame features a 1.8-inch-diagonal, 160-by-123-pixel LCD screen and weighs just 7 ounces. It can store up to 40 digital photos (transferred via an included USB cable) and has a specced battery life of 3 hours.

Canary Wireless Digital Hotspotter

Lots of companies sell keychain-size Wi-Fi signal finders, but the Canary Wireless Digital Hotspotter HS-20 ($50) is different: It shows you not only the signal strength and network type (802.11b/g/n), but also whether the network is encrypted. That makes the Hotspotter a breath of fresh air for travelers who are tired of pulling out their laptop to use a Wi-Fi signal, only to be hit with a password prompt.